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Sheet 1.-

4 Sheets Patented May 7, 1889.

J. BAIRD.

STEAM BOILBR.

`('No Model.)

00. .000990000 OOOOOOOO L1.Shemzs--Sheet 2.

J. BAIRD. STEAM BOILER.

(No Model.)

No. 402.887. Patented May '7, 1889.

N, PETERS, PhnwLdhngnphen Wahinginn. D. C.

(No Model.) 4 sheets-sheet 3.

J.- BAIRD.

STEAM BOILBR.

No. 402,887. Patented May '7, 1889. l [l C w 'N *N N H. L o o Fo o Q1 ,f :o H bw J L. l

F Inventor Lozn cwrd N. PETERS. PholLnnngmphar. Wlshngnn. D. C.

(No Model.) 4 'sheets-sheet 4.

J. BA1-RD.

STEAM BOILER.- No. 402,887. Patented May 7, 1889.

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'lzeses JU?, Baard N. PETERS. Phummhagupmr, washngwn. D. C.

PATENT OFFICE.

JOI-IN BAIRD, OF NEW YORK, N. Y.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 402,887, dated May Application iiled April 25, 1888.

To all whom it may concern: l

Be it known that I, JOHN BAIRD, of the city, county, and State of New York, have invented certain new and useful Improvements in Steam-Boilers and I d0 hereby declare that the following, taken in connection with the drawings, is a full, clear, and exact des 3ription thereof.

It is now well known to constructers and users of steam-boilers that the surface thereof immediately above the fuel in the furnace is much more effective asa heating-surface in proportion to the amount thereof than the surface of the flues or tubes or any other surface in the boiler. Much ingenuity has been expended in contriving means for increasing such surface in proportion to a given or predetermined size of fire-box or furnace, and a plan dating as far back as the time of Watt is to corrugate the surface of the boiler above the furnace, while at the present day it is usual to corrugate the large cylindrical flues which serve as the fire-boxes of marine boilers, in which a high pressure of steam is carried.

My first improvement relates to a new plan for obtaining such extended surface, and also acquiring strength to withstand a high pressure of steam wit-hout going to the expense of corrugating the iron or steel, and with the advantage of requiring no extra skill on the part of Athe workman in constructing the boiler.

It has also been customary for a long time to dry or superheat the steam generated in a boiler, 4either by means of steam-chimneys (the usual manner in this country) or by passing flues or tubes through the steam-space of the boiler.

In my plan I take a certain portion of the products of combustion, depending upon the area of the i'lues, through which it passes either from the fire-box itself or from the back connection of the boiler, and pass this portion of the hot and burning gases, by means of a tube, iirst through awater-space to the outside of the boiler, and thence back again into the steam-space of the boiler, and iinally into the uptake or chimney.

In most of the drawings I have shown both these features of invention as applied to the Serial No. 271,793. (No model.)

same boilers; but they may be used separately. I also have shown in most of the drawings these features as used in boilers provided with a cradle such as was patented to me January 12, 1886, No. 334,156; but these improvements can be used in connection with ordinary forms of water-legs or ordinary fireboxes or masonry setting. n

In the drawings, Figure 1 is a front kelevation of a marine boiler provided with its cradle, showing the tube ends in full lines. Fig. 2 is a rear elevation of the same without the cradle. Fig. 3 is a vertical longitudinal section through Fig.1. Fig. 4 is a side elevation of Fig. 2. Fig. 5 is a side elevation. Fig. 6 is a horizontal section, and Fig. 7 is a front elevation, of the cradle. vation of a boiler of the locomotive type with its cradle. Fig. 9 is a front elevation of the same without the cradle. Fig. 10 is a vertical cross-section through the boiler between the fire-box and the smoke-box 'or back connection. Fig. 11 is a vertical longitudinal section through the boiler and the cradle. Fig. 12 is a side elevation of the boiler without the cradle; and Figs. 13, 14, 15, and 16 are respectively a plan, a front elevation, a longitudinal section, and a rear elevation of the cradle. Fig. 17 is a longitudinal section through an ordinary locomotive-boiler with my superheating or drying device applied thereto. Fig. 18 is a vertical cross-section through the rebox of the same. Figs. 19 to 22,inclusive, are sketches of details on a large scale. Fig. 19 explains the mode of making and the preferred way of bracing the reversed arches that lie over the fire. Fig. 2O shows how the bracing may be attached to the upper part of the shell. Fig. 21 is an elevation of the adjoining portion of Fig. 19. Fig. 22 is a side elevation of the preferred mode of securing the transverse braces.

My plan for securing additional fire-surface above the fuel is to form that part of the boiler of a series of inverted arches, each arch composed transversely of a single sheet of boile iron or steel, and with the adjoining edges of these sheets at the spring of the arch riveted to each other, while the outer edges of those sheets which form the two outside arches are riveted to the shell of the boiler when the Fig. 8 is a front ele- IOO cradle is used, and to the fire-box or to a vertical brace-sheet extending to the top of the boiler, or to both, when an ordinary non-detachable fire-box or ordinary water-legs are employed.

In cases where sheets of sutlicient size can be secured I prefer to make each inverted arch of a single sheet; but when such cannot be had I make each arch ot two or more sheets riveted together. The edges of these sheets are to be riveted, as seen at a a, Fig. 20, so that neither the rivets nor their heads are exposed to the fire. The arches themselves are represented in all the figures at b h, and their adjoining edges are in all cases to be braced to the top of the shell, in the way shown in Figs. 19, 20, and 21. In these iigures the adjoining' edges of the sheets forming the arches are extended into the waterspaceof the-boiler, as at c. A sheet of boileriron orsteel is then secured to the upper part of the shell by angle-irons, or in any other known Way, as represented at d d. I prefer to have the sheets f f as long as the meeting line of the arches, a-nd they depend to the upper edges of the sheets that form two adjoining arches, and the three sheets-wiz., those of two adjoining arches and the brace-sheetare all secured together by splice-plates g g and rivets 7L h. I intend usually to apply another row of rivets, Zak, to fasten the edges of the adjoining arches. The brace-sheets ff should by preference have holes or openings in them at intervals, so that water and steam may communicate freely from the space Vover one inverted arch to that over another. I intend sometimes to dispense with the spliceplates, and in that case to extend the sheets ff down between the adjoining sheets b b of the arches, and then secure these three sheets together :by a row or rows of rivets passing' through all three sheets.

The shells should be braced from side to side at the spring-line of the inverted arches, or thereabout. Such braces are shown at m m. I pass the ends of these braces through the sheets both of the Varch and the shell, then through an outside washer, m', Figs. l!) and 22, and finally through a nut, m2. These braces pass also through holes in the sheets forming the arches, (see Figs. 19, 20, and 21,) andare set up by turning the nuts m2. I preferte provide these braces near their` ends with inside bearing-nuts, m3. There may be two or more of these inverted arches over each grate-surface, and it will be seen that they can be braced so as to resist great internal pressure, and as they need bracing only at ythe spring-lines, no rivet-heads which attach braces and no ends of screw bracebolts are exposed to the fire, as is ordinary flat-topped or even topped fire-boxes.

the case in corrugatetb The tubes marked x in Figs. l, 5, and G are tubes connected with the cradles, and these gures show how such tubes may be disposed so as to secure additional fire-box heating-surface.

The Iiues or tubes for superheating or drying the steam are shown at 0. In the case of boilers with return-fines such as are shown in Figs. 1,2, 3, and 4 these superheating-fiues lead from the back connection, thence through the water-space at the back of the boiler, then upward outside of the boiler, then through the shell into the steam-space, and end nallyv in the uptake or front connection. In the case of boilers of t-he locomotive type (see Figs. 8, 9, 10, 1l, 17, and 18) these superheating-fines lead from the fire-box through the walls of the box, thence upward and through the shell into the steam-space, and finally to the smoke-box. In vboth cases 'it is essential that these lines shall receive only a part ot' the products of combustion on their way to the chimney, andthat they shall pass through the steam-space of the boiler, by preference, some distance above the 'waterlevel; but the precise location in the `tire-box or connection of their open ends at-which the gases enter is unimportant. I intend in some cases to provide these drying or su perheating flues with dampers, being enabled thus to `close or partially close them to the passage of gases, thus regulating in a measure the amount or 95 extent of superheating or drying the steam.

No precise rule can be given for the number or area of these tubes in any given boiler. The constructer must exercise his judgment on these points. The boilers are of course to Ioo be provided with ordinary steam-pipes and such other usual accessories as lmay be required.

I claim as my own inventionl. Two or more inverted arches formed in 105 that part ot a boiler which overlies the furnace, said arches being constructed of sheets 'of metal with their adjoining edges secured by rivets, as described, and having such adjoining edges braced to the upper part-of the 11o shell by sheets of boiler-iron or steel secured to the adjoining edges of the arches and to the shell, substantially as specified.

2. One or more inverted arches formed in that part of a boiler which overlies the furnace, and constructed substantially as dcscribed, in combination with horizontal bracing extending from `outside to outside of the `shell and secured by nuts, as described.

In testimony whereof I have hereunto `sub- 12o scribed my name.

JOHN BAIRD. XVitnessesr W. II. II. YOUNG, ADDISON W. BAIRD. 

